Results: Japanese researchers lowered the operating temperature of solid-oxide fuel cells by changing the structure of their electrode materials. They improved the power output of the cells at 600 °C by an order of magnitude.

Why it matters: Solid-oxide fuel cells can efficiently convert a variety of fuels, such as hydrogen and diesel, into electricity. But because they typically operate at temperatures above 700 °C, they require expensive materials, wear out relatively quickly, and are limited to stationary applications. Compared with other approaches to lowering the operating temperature of fuel cells, the new method has the advantage of using conventional materials that are relatively inexpensive. The new fuel cells could eventually be useful as auxiliary power sources to extend the range of electric vehicles, among other applications.

Methods: The researchers used established processes to fabricate tubular fuel cells 1.9 millimeters in diameter. To produce anodes with different structures, they heat-treated the tubes–which consist of a zirconia-based ceramic and a nickel-oxide mixture–at three temperatures lower than those ordinarily used in fuel-cell production. The resulting anodes were unusually porous, which proved to increase the performance of fuel cells based on them.

Next steps: The researchers established that they can bundle the microtubular fuel cells, but they need to develop ways to turn the bundles into modules that generate enough power for commercial applications.